Field-based upsampling method for performing zoom in a digital video system

Abstract

A video processing system that processes vertical column of pixels from individual fields is disclosed. The video processing system processes pixels from an even field independent of the pixels in the odd field, and vice versa. The video processing system preferably includes a system memory for storing fields of input video images and a vertical filter coupled to the system memory via a data bus. The field data is retrieved from the system memory by the vertical filter and processed as individual fields. The vertical filter preferably calculates a 2x enlargement of the input image, although the filter can be adapted to enlarge by different factors if desired. The enlargement process generally involves representing an input image with twice as many lines of pixels values as the initial image. The values that are used to represent the enlarged pixels are preferably weighted averages of the pixels from an input pixel field. The vertical filter calculates the weighted averages using coefficients that are based on the proximity of the resulting enlarged pixel values to the corresponding pixels from the input field.

What is claimed is: 
     
       1. A video processing system for processing video values that represent a plurality of lines of pixel values in a field-based structure, comprising: a host microcontroller;   a system memory that stores even and odd fields of video data; and   a vertical filter that receives at least a portion of a column of initial pixel values and calculates weighted averages of said initial pixel values to calculate individual fields of pixel values representative of an enlarged image of said initial pixel values, and where said vertical filter increases the number of pixel lines used to represent the initial pixel values;   said weighted averages calculated using coefficients that are based on the relative proximity of the lines of pixels representing said enlarged image to the location of the lines representing said initial pixel values, said coefficients selected from the group consisting of 3/8, 5/8, 1/8, and 7/8;   wherein said vertical filter performs a 2× zoom on said initial pixel values.   
     
     
       2. A method of enlarging an input digital video image to generate an enlarged output image comprising: reading initial pixel values representing the video image to be enlarged from a system memory;   increasing the number of pixels used to represent the video image to be enlarged;   calculating weighted averages of the initial pixel values by multiplying a first initial pixel value by a coefficient selected from the group consisting of 5/8, 1/8, 15/16, 11/16, 7/16, and 3/16 and a second initial pixel value by a coefficient selected from the group consisting of 3/8, 7/8, 1/16, 5/16, 9/16, and 13/16 and adding the resulting products together; and   applying said weighted averages to said increased number of pixels to produce newly calculated pixel values.